$OpenBSD: patch-third_party_usrsctp_BUILD_gn,v 1.2 2017/04/19 05:16:47 robert Exp $
--- third_party/usrsctp/BUILD.gn.orig.port	Sun Aug 14 16:32:41 2016
+++ third_party/usrsctp/BUILD.gn	Sun Aug 14 16:33:15 2016
@@ -107,9 +107,14 @@ static_library("usrsctp") {
     "-UINET6",
   ]
 
-  if (is_linux || is_android) {
+  if ((is_linux && !is_openbsd) || is_android) {
     defines += [
       "__Userspace_os_Linux",
+      "_GNU_SOURCE",
+    ]
+  } else if (is_openbsd) {
+    defines += [
+      "__Userspace_os_OpenBSD",
       "_GNU_SOURCE",
     ]
   } else if (is_mac || is_ios) {
